aufs3.12 mmap patch

diff --git a/fs/buffer.c b/fs/buffer.c
index 6024877..95bbf13 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -2446,7 +2446,7 @@ int block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,
 	 * Update file times before taking page lock. We may end up failing the
 	 * fault so this update may be superfluous but who really cares...
 	 */
-	file_update_time(vma->vm_file);
+	vma_file_update_time(vma);
 
 	ret = __block_page_mkwrite(vma, vmf, get_block);
 	sb_end_pagefault(sb);
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 1485e38..65eeaf3 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1816,7 +1816,7 @@ static int proc_map_files_get_link(struct dentry *dentry, struct path *path)
 	down_read(&mm->mmap_sem);
 	vma = find_exact_vma(mm, vm_start, vm_end);
 	if (vma && vma->vm_file) {
-		*path = vma->vm_file->f_path;
+		*path = vma_pr_or_file(vma)->f_path;
 		path_get(path);
 		rc = 0;
 	}
diff --git a/fs/proc/nommu.c b/fs/proc/nommu.c
index ccfd99b..1f584c3 100644
--- a/fs/proc/nommu.c
+++ b/fs/proc/nommu.c
@@ -45,7 +45,10 @@ static int nommu_region_show(struct seq_file *m, struct vm_region *region)
 	file = region->vm_file;
 
 	if (file) {
-		struct inode *inode = file_inode(region->vm_file);
+		struct inode *inode;
+
+		file = vmr_pr_or_file(region);
+		inode = file_inode(file);
 		dev = inode->i_sb->s_dev;
 		ino = inode->i_ino;
 	}
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 390bdab..6030cbf 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -272,7 +272,10 @@ show_map_vma(struct seq_file *m, struct vm_area_struct *vma, int is_pid)
 	const char *name = NULL;
 
 	if (file) {
-		struct inode *inode = file_inode(vma->vm_file);
+		struct inode *inode;
+
+		file = vma_pr_or_file(vma);
+		inode = file_inode(file);
 		dev = inode->i_sb->s_dev;
 		ino = inode->i_ino;
 		pgoff = ((loff_t)vma->vm_pgoff) << PAGE_SHIFT;
@@ -1412,6 +1415,7 @@ static int show_numa_map(struct seq_file *m, void *v, int is_pid)
 	seq_printf(m, "%08lx %s", vma->vm_start, buffer);
 
 	if (file) {
+		file = vma_pr_or_file(vma);
 		seq_printf(m, " file=");
 		seq_path(m, &file->f_path, "\n\t= ");
 	} else if (vma->vm_start <= mm->brk && vma->vm_end >= mm->start_brk) {
diff --git a/fs/proc/task_nommu.c b/fs/proc/task_nommu.c
index 56123a6..bf84989 100644
--- a/fs/proc/task_nommu.c
+++ b/fs/proc/task_nommu.c
@@ -149,7 +149,10 @@ static int nommu_vma_show(struct seq_file *m, struct vm_area_struct *vma,
 	file = vma->vm_file;
 
 	if (file) {
-		struct inode *inode = file_inode(vma->vm_file);
+		struct inode *inode;
+
+		file = vma_pr_or_file(file);
+		inode = file_inode(file);
 		dev = inode->i_sb->s_dev;
 		ino = inode->i_ino;
 		pgoff = (loff_t)vma->vm_pgoff << PAGE_SHIFT;
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 8b6e55e..5cf4c4d 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1017,6 +1017,28 @@ static inline int fixup_user_fault(struct task_struct *tsk,
 }
 #endif
 
+#ifdef CONFIG_MMU
+extern void vma_do_file_update_time(struct vm_area_struct *, const char[], int);
+extern struct file *vma_do_pr_or_file(struct vm_area_struct *, const char[],
+				      int);
+extern void vma_do_get_file(struct vm_area_struct *, const char[], int);
+extern void vma_do_fput(struct vm_area_struct *, const char[], int);
+
+#define vma_file_update_time(vma)	vma_do_file_update_time(vma, __func__, \
+								__LINE__)
+#define vma_pr_or_file(vma)		vma_do_pr_or_file(vma, __func__, \
+							  __LINE__)
+#define vma_get_file(vma)		vma_do_get_file(vma, __func__, __LINE__)
+#define vma_fput(vma)			vma_do_fput(vma, __func__, __LINE__)
+#else
+extern struct file *vmr_do_pr_or_file(struct vm_region *, const char[], int);
+extern void vmr_do_fput(struct vm_region *, const char[], int);
+
+#define vmr_pr_or_file(region)		vmr_do_pr_or_file(region, __func__, \
+							  __LINE__)
+#define vmr_fput(region)		vmr_do_fput(region, __func__, __LINE__)
+#endif /* CONFIG_MMU */
+
 extern int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write);
 extern int access_remote_vm(struct mm_struct *mm, unsigned long addr,
 		void *buf, int len, int write);
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index d9851ee..4bde7bf 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -213,6 +213,7 @@ struct vm_region {
 	unsigned long	vm_top;		/* region allocated to here */
 	unsigned long	vm_pgoff;	/* the offset in vm_file corresponding to vm_start */
 	struct file	*vm_file;	/* the backing file or NULL */
+	struct file	*vm_prfile;	/* the virtual backing file or NULL */
 
 	int		vm_usage;	/* region usage count (access under nommu_region_sem) */
 	bool		vm_icache_flushed : 1; /* true if the icache has been flushed for
@@ -281,6 +282,7 @@ struct vm_area_struct {
 	unsigned long vm_pgoff;		/* Offset (within vm_file) in PAGE_SIZE
 					   units, *not* PAGE_CACHE_SIZE */
 	struct file * vm_file;		/* File we map to (can be NULL). */
+	struct file *vm_prfile;		/* shadow of vm_file */
 	void * vm_private_data;		/* was vm_pte (shared mem) */
 
 #ifndef CONFIG_MMU
diff --git a/kernel/fork.c b/kernel/fork.c
index 086fe73..003e30c 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -412,7 +412,7 @@ static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
 			struct inode *inode = file_inode(file);
 			struct address_space *mapping = file->f_mapping;
 
-			get_file(file);
+			vma_get_file(tmp);
 			if (tmp->vm_flags & VM_DENYWRITE)
 				atomic_dec(&inode->i_writecount);
 			mutex_lock(&mapping->i_mmap_mutex);
diff --git a/mm/Makefile b/mm/Makefile
index 305d10a..662e496 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -17,7 +17,7 @@ obj-y			:= filemap.o mempool.o oom_kill.o fadvise.o \
 			   util.o mmzone.o vmstat.o backing-dev.o \
 			   mm_init.o mmu_context.o percpu.o slab_common.o \
 			   compaction.o balloon_compaction.o \
-			   interval_tree.o list_lru.o $(mmu-y)
+			   interval_tree.o list_lru.o prfile.o $(mmu-y)
 
 obj-y += init-mm.o
 
diff --git a/mm/filemap.c b/mm/filemap.c
index ae4846f..3f890ee 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1735,7 +1735,7 @@ int filemap_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 	int ret = VM_FAULT_LOCKED;
 
 	sb_start_pagefault(inode->i_sb);
-	file_update_time(vma->vm_file);
+	vma_file_update_time(vma);
 	lock_page(page);
 	if (page->mapping != inode->i_mapping) {
 		unlock_page(page);
diff --git a/mm/fremap.c b/mm/fremap.c
index 5bff081..107fe99 100644
--- a/mm/fremap.c
+++ b/mm/fremap.c
@@ -207,15 +207,26 @@ get_write_lock:
 		 */
 		if (mapping_cap_account_dirty(mapping)) {
 			unsigned long addr;
-			struct file *file = get_file(vma->vm_file);
+			struct file *file = vma->vm_file,
+				*prfile = vma->vm_prfile;
 
+			vma_get_file(vma);
 			addr = mmap_region(file, start, size,
 					vma->vm_flags, pgoff);
-			fput(file);
+			vma_fput(vma);
 			if (IS_ERR_VALUE(addr)) {
 				err = addr;
 			} else {
 				BUG_ON(addr != start);
+				if (prfile) {
+					struct vm_area_struct *new_vma;
+
+					new_vma = find_vma(mm, addr);
+					if (!new_vma->vm_prfile)
+						new_vma->vm_prfile = prfile;
+					if (new_vma != vma)
+						get_file(prfile);
+				}
 				err = 0;
 			}
 			goto out;
diff --git a/mm/madvise.c b/mm/madvise.c
index 539eeb9..5e700b1 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -327,12 +327,12 @@ static long madvise_remove(struct vm_area_struct *vma,
 	 * vma's reference to the file) can go away as soon as we drop
 	 * mmap_sem.
 	 */
-	get_file(f);
+	vma_get_file(vma);
 	up_read(&current->mm->mmap_sem);
 	error = do_fallocate(f,
 				FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
 				offset, end - start);
-	fput(f);
+	vma_fput(vma);
 	down_read(&current->mm->mmap_sem);
 	return error;
 }
diff --git a/mm/memory.c b/mm/memory.c
index d176154..49cafa9 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2745,7 +2745,7 @@ reuse:
 			set_page_dirty_balance(dirty_page, page_mkwrite);
 			/* file_update_time outside page_lock */
 			if (vma->vm_file)
-				file_update_time(vma->vm_file);
+				vma_file_update_time(vma);
 		}
 		put_page(dirty_page);
 		if (page_mkwrite) {
@@ -3456,7 +3456,7 @@ static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma,
 
 		/* file_update_time outside page_lock */
 		if (vma->vm_file && !page_mkwrite)
-			file_update_time(vma->vm_file);
+			vma_file_update_time(vma);
 	} else {
 		unlock_page(vmf.page);
 		if (anon)
diff --git a/mm/mmap.c b/mm/mmap.c
index 9d54851..64ae6ce 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -250,7 +250,7 @@ static struct vm_area_struct *remove_vma(struct vm_area_struct *vma)
 	if (vma->vm_ops && vma->vm_ops->close)
 		vma->vm_ops->close(vma);
 	if (vma->vm_file)
-		fput(vma->vm_file);
+		vma_fput(vma);
 	mpol_put(vma_policy(vma));
 	kmem_cache_free(vm_area_cachep, vma);
 	return next;
@@ -860,7 +860,7 @@ again:			remove_next = 1 + (end > next->vm_end);
 	if (remove_next) {
 		if (file) {
 			uprobe_munmap(next, next->vm_start, next->vm_end);
-			fput(file);
+			vma_fput(vma);
 		}
 		if (next->anon_vma)
 			anon_vma_merge(vma, next);
@@ -1622,8 +1622,8 @@ out:
 unmap_and_free_vma:
 	if (vm_flags & VM_DENYWRITE)
 		allow_write_access(file);
+	vma_fput(vma);
 	vma->vm_file = NULL;
-	fput(file);
 
 	/* Undo any partial mapping done by a device driver. */
 	unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end);
@@ -2412,7 +2412,7 @@ static int __split_vma(struct mm_struct * mm, struct vm_area_struct * vma,
 		goto out_free_mpol;
 
 	if (new->vm_file)
-		get_file(new->vm_file);
+		vma_get_file(new);
 
 	if (new->vm_ops && new->vm_ops->open)
 		new->vm_ops->open(new);
@@ -2431,7 +2431,7 @@ static int __split_vma(struct mm_struct * mm, struct vm_area_struct * vma,
 	if (new->vm_ops && new->vm_ops->close)
 		new->vm_ops->close(new);
 	if (new->vm_file)
-		fput(new->vm_file);
+		vma_fput(new);
 	unlink_anon_vmas(new);
  out_free_mpol:
 	mpol_put(vma_policy(new));
@@ -2828,7 +2828,7 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
 			if (anon_vma_clone(new_vma, vma))
 				goto out_free_mempol;
 			if (new_vma->vm_file)
-				get_file(new_vma->vm_file);
+				vma_get_file(new_vma);
 			if (new_vma->vm_ops && new_vma->vm_ops->open)
 				new_vma->vm_ops->open(new_vma);
 			vma_link(mm, new_vma, prev, rb_link, rb_parent);
diff --git a/mm/msync.c b/mm/msync.c
index 632df45..02d770e 100644
--- a/mm/msync.c
+++ b/mm/msync.c
@@ -80,10 +80,10 @@ SYSCALL_DEFINE3(msync, unsigned long, start, size_t, len, int, flags)
 		start = vma->vm_end;
 		if ((flags & MS_SYNC) && file &&
 				(vma->vm_flags & VM_SHARED)) {
-			get_file(file);
+			vma_get_file(vma);
 			up_read(&mm->mmap_sem);
 			error = vfs_fsync(file, 0);
-			fput(file);
+			vma_fput(vma);
 			if (error || start >= end)
 				goto out;
 			down_read(&mm->mmap_sem);
diff --git a/mm/nommu.c b/mm/nommu.c
index ecd1f15..d4306cd 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -652,7 +652,7 @@ static void __put_nommu_region(struct vm_region *region)
 		up_write(&nommu_region_sem);
 
 		if (region->vm_file)
-			fput(region->vm_file);
+			vmr_fput(region);
 
 		/* IO memory and memory shared directly out of the pagecache
 		 * from ramfs/tmpfs mustn't be released here */
@@ -810,7 +810,7 @@ static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma)
 	if (vma->vm_ops && vma->vm_ops->close)
 		vma->vm_ops->close(vma);
 	if (vma->vm_file)
-		fput(vma->vm_file);
+		vma_fput(vma);
 	put_nommu_region(vma->vm_region);
 	kmem_cache_free(vm_area_cachep, vma);
 }
@@ -1376,7 +1376,7 @@ unsigned long do_mmap_pgoff(struct file *file,
 					goto error_just_free;
 				}
 			}
-			fput(region->vm_file);
+			vmr_fput(region);
 			kmem_cache_free(vm_region_jar, region);
 			region = pregion;
 			result = start;
@@ -1452,10 +1452,10 @@ error_just_free:
 	up_write(&nommu_region_sem);
 error:
 	if (region->vm_file)
-		fput(region->vm_file);
+		vmr_fput(region);
 	kmem_cache_free(vm_region_jar, region);
 	if (vma->vm_file)
-		fput(vma->vm_file);
+		vma_fput(vma);
 	kmem_cache_free(vm_area_cachep, vma);
 	kleave(" = %d", ret);
 	return ret;
diff --git a/mm/prfile.c b/mm/prfile.c
new file mode 100644
index 0000000..fc708d2
--- /dev/null
+++ b/mm/prfile.c
@@ -0,0 +1,86 @@
+/*
+ * Mainly for aufs which mmap(2) diffrent file and wants to print different path
+ * in /proc/PID/maps.
+ * Call these functions via macros defined in linux/mm.h.
+ *
+ * See Documentation/filesystems/aufs/design/06mmap.txt
+ *
+ * Copyright (c) 2014 Junjro R. Okajima
+ * Copyright (c) 2014 Ian Campbell
+ */
+
+#include <linux/mm.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+
+/* #define PRFILE_TRACE */
+static inline void prfile_trace(struct file *f, struct file *pr,
+			      const char func[], int line, const char func2[])
+{
+#ifdef PRFILE_TRACE
+	if (pr)
+		pr_info("%s:%d: %s, %p\n", func, line, func2,
+			f ? (char *)f->f_dentry->d_name.name : "(null)");
+#endif
+}
+
+#ifdef CONFIG_MMU
+void vma_do_file_update_time(struct vm_area_struct *vma, const char func[],
+			     int line)
+{
+	struct file *f = vma->vm_file, *pr = vma->vm_prfile;
+
+	prfile_trace(f, pr, func, line, __func__);
+	file_update_time(f);
+	if (f && pr)
+		file_update_time(pr);
+}
+
+struct file *vma_do_pr_or_file(struct vm_area_struct *vma, const char func[],
+			       int line)
+{
+	struct file *f = vma->vm_file, *pr = vma->vm_prfile;
+
+	prfile_trace(f, pr, func, line, __func__);
+	return (f && pr) ? pr : f;
+}
+
+void vma_do_get_file(struct vm_area_struct *vma, const char func[], int line)
+{
+	struct file *f = vma->vm_file, *pr = vma->vm_prfile;
+
+	prfile_trace(f, pr, func, line, __func__);
+	get_file(f);
+	if (f && pr)
+		get_file(pr);
+}
+
+void vma_do_fput(struct vm_area_struct *vma, const char func[], int line)
+{
+	struct file *f = vma->vm_file, *pr = vma->vm_prfile;
+
+	prfile_trace(f, pr, func, line, __func__);
+	fput(f);
+	if (f && pr)
+		fput(pr);
+}
+#else
+struct file *vmr_do_pr_or_file(struct vm_region *region, const char func[],
+			       int line)
+{
+	struct file *f = region->vm_file, *pr = region->vm_prfile;
+
+	prfile_trace(f, pr, func, line, __func__);
+	return (f && pr) ? pr : f;
+}
+
+void vmr_do_fput(struct vm_region *region, const char func[], int line)
+{
+	struct file *f = region->vm_file, *pr = region->vm_prfile;
+
+	prfile_trace(f, pr, func, line, __func__);
+	fput(f);
+	if (f && pr)
+		fput(pr);
+}
+#endif /* CONFIG_MMU */
